U.S. military officials said they could not immediately recall another case in which a senior military officer was required to draw their weapon.

The Thursday attack happened during a high-level meeting at Kandahar Palace. A gunman wearing an Afghan army uniform opened fire on officials meeting with Miller, killing Gen. Abdul Raziq, the region’s police chief, and intelligence chief Gen. Abdul Momin, as well as wounding two Americans. The shooter was shot and killed by U.S. troops.

But the Taliban later said the attack, which caused the delay of elections in Kandahar, was directed at Raziq and Miller, who took over last month as the top U.S. commander in Afghanistan, replacing Gen. John Nicholson.

“We remain absolutely committed to an Afghan-led Afghan reconciliation,” Mattis said. “We need to find who’s done this, but right now, we are going toward the election and we will continue to defend the Afghan people.”